Current difference sensors, systems and methods

ABSTRACT

Embodiments relate to current difference sensors, systems and methods. In an embodiment, a current difference sensor includes first and second conductors arranged relative to one another such that when a first current flows through the first conductor and a second current, equal to the first current, flows through the second conductor, a first magnetic field induced in the first conductor and a second magnetic field induced in the second conductor cancel each other at a first position and a second position; and first and second magnetic field sensing elements arranged at the first and second positions, respectively.

REFERENCE TO RELATED APPLICATION

This application is a continuation of U.S. application Ser. No.13/012,096 filed on Jan. 24, 2011.

TECHNICAL FIELD

The invention relates generally to current sensors and more particularlyto current difference sensors suitable, for example, for sensing smallcurrent differences.

BACKGROUND

Conventional current difference sensing systems often use a ring-shapedferrite. Two wires are coupled to the ring such that two currents flowthrough the ring in opposite directions and their flux contributionscancel. If the two currents are different, a net flux is carried by theferrite, which can be detected by a secondary winding and processedelectronically.

While such systems can be effective for detecting current differences,they provide only limited information. For example, they can detectwhether |I1−I2|>threshold but do not provide any reliable informationregarding I1+I2 or I1−I2.

Therefore, there is a need for improved current difference sensingsystems and methods.

SUMMARY

Current difference sensors, systems and methods are disclosed. In anembodiment, a current difference sensor comprises first and secondconductors arranged relative to one another such that when a firstcurrent flows through the first conductor and a second current, equal tothe first current, flows through the second conductor, a first magneticfield caused by the first current and a second magnetic field caused bythe second current cancel each other at a first position and a secondposition; and first and second magnetic field sensing elements arrangedto detect the first and second magnetic fields.

In an embodiment, a method comprises inducing a first current to flow ina first conductor; inducing a second current to flow in a secondconductor; arranging the first and second conductors such that at leastone component of a total magnetic field caused by the first and secondcurrents is approximately zero in at least two locations when the firstand second currents are approximately equal; positioning magnetic fieldsensors in the at least two locations; and determining a differencebetween the first and second currents based on sensed magnetic fields.

In an embodiment, a method comprises arranging a first conductor spacedapart from and substantially parallel to a second conductor; arranging adie proximate the first and second conductors; and arranging a pluralityof magnetic field sensing elements on a first surface of the die todetect magnetic fields caused by first and second currents in the firstand second conductors, respectively, and determine a difference betweenthe first and second currents based on the magnetic fields.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention may be more completely understood in consideration of thefollowing detailed description of various embodiments of the inventionin connection with the accompanying drawings, in which:

FIG. 1 depicts a side cross-sectional view of a current differencesensor according to an embodiment.

FIG. 2 depicts a side cross-sectional view of a current differencesensor according to an embodiment.

FIG. 3 depicts a side cross-sectional view of a current differencesensor according to an embodiment.

FIG. 4 depicts a graph of magnetic fields for various die and conductorarrangements according to an embodiment.

FIG. 5 depicts a side cross-sectional view of a current differencesensor according to an embodiment.

FIG. 6 depicts a side cross-sectional view of a current differencesensor according to an embodiment.

FIG. 7 depicts a side cross-sectional view of a current differencesensor according to an embodiment.

FIG. 8 depicts a side cross-sectional view of a current differencesensor according to an embodiment.

FIG. 9 depicts orthogonal magnetic field sensor elements according to anembodiment.

FIG. 10A depicts a side cross-sectional view of a current differencesensor according to an embodiment.

FIG. 10B depicts a top plan view of the current difference sensor ofFIG. 10A.

FIG. 11 depicts a side cross-sectional view of a current differencesensor according to an embodiment.

FIG. 12 depicts a side cross-sectional view of a current differencesensor according to an embodiment.

FIG. 13 depicts a top plan view of a current difference sensor accordingto an embodiment.

FIG. 14A depicts a top plan view of a current difference sensorconductor according to an embodiment.

FIG. 14B depicts a top plan view of a current difference sensorconductor according to an embodiment.

FIG. 14C depicts a top plan view of the current difference sensorconductors of FIGS. 14A and 14B.

FIG. 14D is a side cross-sectional view of the current difference sensorof FIGS. 14A-14C.

While the invention is amenable to various modifications and alternativeforms, specifics thereof have been shown by way of example in thedrawings and will be described in detail. It should be understood,however, that the intention is not to limit the invention to theparticular embodiments described. On the contrary, the intention is tocover all modifications, equivalents, and alternatives falling withinthe spirit and scope of the invention as defined by the appended claims.

DETAILED DESCRIPTION

Embodiments relate to current difference sensors. In variousembodiments, a current difference sensor can compare two currents anddetect a difference therebetween. In one embodiment, the detectabledifference can be as small as about 10 mA for currents in a range ofabout zero to about 30 A, though this can vary in other embodiments.Additionally, embodiments can provide reduced delay times, such as belowabout 1 microsecond, and provide information regarding I1+I2 as well asI1−I2. Further, embodiments are small in size, robust againstinterference and inexpensive.

Embodiments comprise two conductors arranged such that when equalcurrents pass therethrough, magnetic field contributions of eachconductor cancel at points at which magnetic field sensor elements,sensing the same magnetic field components, can be arranged. Unequal, ordifference, currents can then be detected, with the componentssubtracted in order to cancel homogeneous background fields.

Referring to FIG. 1, an embodiment of a current difference sensor 100 isdepicted. Sensor 100 comprises two conductors 102 and 104 spaced apartfrom one another on two different planes or levels. A die 106 isarranged therebetween on a third plane or level, and twomagnetoresistors (MRs) 108 and 110 are disposed on die 106. MRs 108 and110 are spaced apart from on another and disposed on a planeapproximately midway between conductors 102 and 104 and thereforebetween currents I1 and I2 in conductors 102 and 104, respectively. Inembodiments, MRs 108 and 110 can comprise anisotropic MRs, giant MRs orsome other MR effect technology.

Because of assembly tolerances and other factors, however, it isvirtually impossible in practice to position MRs 108 and 110 exactlymidway between conductors 102 and 104. The resulting magnetic fields,Bx1 on MR 108 and Bx2 on MR 110, therefore are as follows:

Bx1=(K+dK)*I1−(K−dK)*I2

Bx2=(K′+dK′)*I1−(K′−dK′)*I2

Bx1−Bx2=(K−K′)*(I1−I2)+(dK−dK′)*(I1+I2)

The difference measurement, Bx1−Bx2, is thus corrupted by the sum of thecurrents, I1+I2. One solution to this issue would be to provide severalMRs on the top surface of die 106 and then select the MRs which have thebest suppression of (I1+I2). Because this is generally not a goodsolution, another solution is to add Hall plates to sensor 100, with afirst, H1, arranged proximate MR 108 and a second, H2, arrangedproximate MR 110. Then:

H2−H1=Kz*(I1+I2)

which leads to:

I1−I2=[(Bx1−Bx2)/(K−K′)]−[(dK−dK′(H2−H1)/(Kz*(K−K′))]

An advantage of this configuration is that it has a low resistancebecause conductors 102 and 104, in an embodiment, are simple straightbars. Additionally, information regarding I1+I2 and I1−I2 can beobtained.

Another embodiment is depicted in FIG. 2, in which die 106 is mounted ina slightly tilted orientation with respect to the planes of conductorsII and I2. The tilt angle of die 106 can vary but is generallyconfigured to be larger than worst-case assembly tolerances.Additionally, a plurality of MRs 108 and 110 are arranged on the topsurface of die 106. While only MRs 108 and 110 are visible in FIG. 2,this embodiment of sensor 100 comprises additional MRs arranged in agrid on the top surface of die 106, spaced apart by, for example, 25micrometers along the x-axis. The spacing can vary in other embodiments.After assembly of sensor 100, the signals of all MRs 108 and 110 as wellas the grid are tested, and those having the lowest sensitivity to I1+I2are selected.

Another embodiment is depicted in FIG. 3, in which a small, generallyarbitrary lateral asymmetry is introduced between conductors 102 and104. As in the embodiment of FIG. 2, a grid of MRs 108 and 110 andothers not visible in FIG. 3 is arranged on the top surface of die 106,and those having the lowest sensitivity to I1+I2 are selected. In anembodiment, conductors 102 and 104 are each about 6 mm by about 1 mm andare shifted relative to each other by less than about 1 mm in thex-direction in embodiments, such as by about 0.2 mm in one embodiment.

Because of assembly tolerances, it is assumed, for purposes of thisexample embodiment, that die 106 is tilted by about 1.5 degrees aroundthe symmetry center of conductors 102 and 104. Referring also to FIG. 4,the magnetic field Bx for five different scenarios is depicted, for allof which I1=I2=30 A and z=0.5 mm. For scenario 1, die 206 is shifted 100.mu.m (from center) toward conductor 104. For scenario 2, die 206 isshifted 50 .mu.m (from center) toward conductor 104. For scenario 3, die206 is at center. For scenario 4, die 206 is shifted 50 .mu.m towardconductor 102. For scenario 5, die 206 is shifted 100 .mu.m towardconductor 102.

In back-end test, after die 106 is mounted between conductors 102 and104, the voltage difference of MRs 108-108 n and 110-110 n arranged in agrid on the top surface of die 106 as previously mentioned can bemeasured. Note that the grids of MR108-108 n and MR110-110 n may or maynot overlap in embodiments. As depicted in FIG. 4, the respective gridsdo not overlap. The two MRs having the lowest sensitivity with respectto (I1+I2) can be selected. FIG. 4 shows five curves 1-5 correspondingto five different scenarios 1-5, where each curve represents themagnetic field parallel to the die surface versus x-position. Forscenario 1, FIG. 4 shows that the fired on MR 108 n is equal to thefield on MR 110 n, so that the difference is zero. Thus, in end-of-linetesting, sensor 100 could be trimmed by selecting MR108 n and MR110 n.For scenario 5 in FIG. 4, the field on MR 108 is the same as the one onMR 110. Therefore, these two MRs can be selected during the trimmingprocess. This makes it possible in embodiments to trim sensor 100 suchthat it does not respond to (I1+I2) but rather only (I1−I2). Anymismatch of the MRs is also trimmed by this procedure.

Referring again to FIG. 3, the concept can be generalized. Conductors102 and 104 are of similar shape and carry the same current such thatmidway between the two, the respective magnetic fields of conductors 102and 104 cancel to a large extent, in the sense that the magnitude of thetotal field is much less, e.g. by a factor of 100 or 1,000, than themagnitude of the fields caused by a single conductor. Conductors 102 and104 are formed to have a small asymmetry such that the lateral magneticfield caused by identical currents in both conductors 102 and 104exhibits a small peak at a certain position x for all assemblytolerances between conductors 102 and 104 and die 106. For alltolerances, there is at least one MR (108 or 110) to the left and one MR(110 or 108) to the right of the peak, with the lateral magnetic fieldidentical on both MRs 108 and 110.

The asymmetry depicted in FIG. 3 is obtained by shifting conductor 104slightly laterally with respect to conductor 102. In another embodiment,conductor 104 could be made slightly wider than conductor 102 such thatthe right edges of each are positioned as in FIG. 4 with the left edgesflush. In yet another embodiment, the cross-sectional area of one of theconductors 102 or 104 can be tapered such that it is thicker (in thevertical direction with respect to the orientation of the drawing on thepage) at the left side than the right, or vice-versa. Or, bothconductors 102 and 104 can be tapered yet positioned such that thethicker end of one is flush with the thinner end of the other.

Other embodiments are also possible. In the embodiment of FIG. 5, sensor100 comprises first and second conductors 102 and 104 mounted to abottom side of a printed circuit board (PCB) 114 to isolate theconductors 102 and 104 from die 106, which is mounted to a top side ofPCB 114. In embodiments, PCB 114 can be replaced by some othernon-conducting structure comprising, for example, glass, porcelain orsome other suitable material. Three MRs 108, 110 and 112 are mounted toa top side of die 106. In an embodiment, MRs 108 and 110 are separatedby 1.25 mm, and MRs 110 and 112 are separated by 1.25 mm, such that MRs108 and 112 are separated by 2.5 mm, though these dimensions can vary inembodiments. With currents in conductors 102 and 104 flowing into thedrawing plane as depicted in FIG. 5, MR 108 detects a strong field fromthe current through conductor 102 and weak field from the currentthrough conductor 104, whereas MR 112 responds more strongly to currentthrough conductor 104 than through conductor 102. MR 110 respondsequally to the currents in conductors 102 and 104 such that the field onMR 110 is proportional to the sum of the currents in conductors 102 and104, whereas the fields on the other MRs 108 and 112 are neitherproportional to pure sums nor pure differences of the currents butrather a combination of both.

A challenge with the embodiment of FIG. 5 is balancing sensitivity andsaturation. High sensitivity is desired to measure small magneticfields, but efforts to increase sensitivity, such as reducing thevertical distance between conductors 102 and 104 and MRs 108, 110 and112 and/or the cross-sectional dimensions of conductors 102 and 104, cansend the MRs into saturation such that larger current differences can nolonger be detected. Such an embodiment can be suitable for variousdesired applications, however.

Another embodiment is depicted in FIG. 6, in which sensor 100 comprisesthree conductors 102, 103 and 104. Center conductor 103 can be used to“tune” sensor 100 such that positions are obtained without a magneticfield, and MRs 108 and 110 can then be arranged accordingly to see nonet field. In an embodiment, conductors 102 and 104 are each about 1.2mm by about 1.2 mm, and conductor 103 is about 1.7 mm by about 1.7 mm.Die 106 is coupled to a wafer 116, which is about 200 .mu.m thick andcomprises glass or porcelain or some other suitable material inembodiments and includes through-vias 120. Vias 120 are filled with aconductor, such as a nano-paste, in embodiments. In one embodiment, thesilicon of die 106 is ground down to about 30 .mu.m and adhesivelybonded at its top side to wafer 116. Die(s) 106 can then be cut orotherwise formed into rectangles, and the bottom side(s) and sidewallscoated with a low-temperature dioxide or silicon oxide (SiOx). In anembodiment, the dioxide is about 15 .mu.m thick. MRs 108 and 110 arespaced apart about x=2 mm and are separated from the top side ofconductors 102-104 by about z=50 .mu.m in an embodiment. Conductors102-104, die 106 and wafer 116 are covered by a mold compound 118.

In an embodiment, current flows into the drawing plane (as depicted inFIG. 6) through center conductor 103 and out of the drawing plane(again, as depicted in FIG. 6) through outer conductors 102 and 104,each of which carries about half of the current. MR sensors 108 and 110form a bridge and are arranged at locations where the magnetic fields ofconductor 103 and either of conductors 102 and 104 cancel at equalcurrents.

A further adaptation of sensor 100 of FIG. 6 is depicted in FIG. 7, inwhich sensor 100 comprises a dual-die package. One MR 108 is coupled toan upper die 106 a, and another MR 110 is coupled to a lower die 106 b,with MRs 108 and 110 located on a common axis in an embodiment.Conductors 102 and 104 are similar to conductor 103 in an embodiment andare about 1.7 mm by about 1.7 mm. Such an embodiment can provideadvantages with respect to obtaining information about (I1+I2) andimprove cancellation of background of fields. In an embodiment of sensor100 of FIG. 7, wafers 116 can be omitted.

It can be difficult, because of assembly tolerances and other factors,to arrange MRs 108 and 110 on the same axis, represented by a dashedvertical line in FIG. 7. Therefore, another, potentially more robustembodiment of sensor 100 depicted in FIG. 8 can address this challengeby including additional MRs 109 and 111. In an embodiment, conductors102 and 104 are each about 0.9 mm by about 1.7 mm, and conductor 103 isabout 1.7 mm by about 1.7 mm. Conductors 102-104 are cast into glass 122in an embodiment, and contacts 124 couple PCBs 114 a and 114 b. MRs108-111 are separated from conductors 102-104 by z=about 250 .mu.m inembodiments.

In operation, current I1 flows through conductor 103, while current I2is split into two halves which each flow through one of conductors 102and 104 in the opposite direction of current I1. The signals of MRs 108and 109 are added, as are those of MRs 110 and 111, with the latter thensubtracted from the former. Because MRs 108 and 110 experience strong I1fields, while MRs 109 and 111 experience strong I2 fields of theopposite polarity of I1, lateral positioning shifts of the MRs 108-111are compensated for. Casting conductors 102-104 in glass helps to avoiddimensional changes over the lifetime thereof due to moisture and otherfactors.

A potential drawback of the embodiment of FIG. 8, however, is theexpense of a dual-die solution. In various embodiments, temperature canalso be an issue. To provide temperature compensation, orthogonal MRscan be added, an embodiment of which is depicted in FIG. 9. FIG. 9depicts two MRs 108 and 110, each with an orthogonal MR 108′ and 110′forming half-bridges. Embodiments comprising additional MRs, such asgrids of MRs as discussed herein, can similarly comprise additionalorthogonal MRs. In operation, and with the barber poles as depicted inFIG. 9, MRs 108 and 110 are sensitive to weak fields in the x-direction,while MRs 108′ and 110′ are sensitive to weak fields in the−x-direction. The close arrangements of MRs 108 and 108′, and 110 and110′, ensures that each sees the same magnetic field and temperature.The signals of each half-bridge, U1 and U2, are therefore temperaturecompensated.

Another embodiment of a sensor 100 is depicted in FIG. 10. In thisembodiment, sensor 100 comprises a single die 106, with three MRs 108,109 and 100 mounted on a top surface thereof. Although the dimensionscan vary in embodiments, in one embodiment die 106 can be about 4 mm byabout 1.75 mm, with a thickness of about 200 .mu.mu.m, and MRs 108 and110 are spaced apart by x=about 4 mm. Four conductors 102, 103, 104 and105 are cast into glass 122, similar to the embodiment of FIG. 8, with atop surface of conductors 102-105 spaced apart from MRs 108-110 byz=about 250 .mu.m in an embodiment. As depicted in FIG. 10B, conductors102-105 comprise conductor portions, with conductors 102 and 105, alongwith a connecting portion 101, forming a first generally U-shapedconductor element, and conductors 103 and 104, along with a connectingportion 107, forming a second generally U-shaped conductor element. Across-section of each of conductors 102-105 as depicted in FIG. 10A isabout 1.7 mm by about 1.7 mm in an embodiment. In FIG. 10B, the lengthof conductors 102 and 105 is y=about 10 mm, with a width of x=about 8.3mm of connecting portion 101. A separation distance between adjacentones of the conductors 102-15 is x=about 0.5 mm in the embodimentdepicted.

Advantages of the embodiment of FIG. 10 include a single die, which isless expensive and provides easier assembly, because it does not requirepins for communication with a second die. A single die also providesfewer opportunities for mismatch of the MR sensor elements as well asimproved temperature homogeneity. The MRs of FIG. 10 can compriseorthogonal MRs, such as are depicted in FIG. 9 and discussed above, inembodiments.

Sensor system 100 depicted in FIG. 11 is similar to that of FIG. 10 butcomprises a triple Hall element 128, 129 and 130 system in addition toMRs to measure the sum of the currents I1+I2. Advantages of theembodiment of FIG. 11 include increased robustness against disturbancesand improved tamper-resistance.

On the other hand, Hall elements 128-130 should be positioned closer toconductors 102-105. Therefore, another embodiment (not depicted)comprises Hall elements 128-130 on a bottom side of die 106 and MRs on atop side of die 106. Die 106 can be about 200 .mu.m thick in such anembodiment.

Alternatively, AMRs 108 and 110 can be implemented to measure I1+x*I2(x<<1), as depicted in the embodiment of FIG. 12. AMRs 108 and 100 canbe positioned on a top surface of die 106, which can be about 200 .mu.mthick in an embodiment, such that a separation distance between AMRs 108and 110 and top surfaces of conductors 102-15 is z=about 250 .mu.m. Sucha system is generally robust against background fields, though not asrobust as the triple Hall embodiment of FIG. 11. The small dampingeffect, x, is due to the distance between conductors 102 and 105,through which current I2 flows, and AMRs 108 and 110.

In the embodiment of FIG. 13, a return path for I2 is omitted, such thatonly three conductors 102-104 are implemented. The conductors 102-104,however, can be made wider, such as x=about 3.5 mm for each ofconductors 103 and 104 and x=about 6 mm for conductor 102, anddissipation reduced by about 50%. A separation distance betweenconductors 103 and 104 is still x=about 0.5 mm in an embodiment, and alength of conductor 102 is y=about 10 mm in an embodiment.

Yet another embodiment is depicted in FIG. 14, in which sensor system100 comprises a multi-level conductor 132, at least somewhat similar tothe embodiments discussed above with respect to FIGS. 1-4. Conductor 132(FIG. 14C) comprises a first layer 134 (FIG. 14A) and a second layer 136(FIG. 14B) in an embodiment. In an embodiment, isolation layers 138 arepositioned between die 106 and conductor level 136, and betweenconductor level 136 and conductor level 134.

Various embodiments of current and current difference sensing anddetermination systems are disclosed. Embodiments can be advantageous byproviding single sensor systems capable of measuring current flow(I1+I2) and leakage currents (I1−I2) while also being small in size,robust against interference and inexpensive when compared withconventional difference current sensor systems. Embodiments can also becombined with an isolated voltage sensor in order to obtain a full powermeasurement.

Various embodiments of systems, devices and methods have been describedherein. These embodiments are given only by way of example and are notintended to limit the scope of the invention. It should be appreciated,moreover, that the various features of the embodiments that have beendescribed may be combined in various ways to produce numerous additionalembodiments. Moreover, while various materials, dimensions, shapes,configurations and locations, etc. have been described for use withdisclosed embodiments, others besides those disclosed may be utilizedwithout exceeding the scope of the invention.

Persons of ordinary skill in the relevant arts will recognize that theinvention may comprise fewer features than illustrated in any individualembodiment described above. The embodiments described herein are notmeant to be an exhaustive presentation of the ways in which the variousfeatures of the invention may be combined. Accordingly, the embodimentsare not mutually exclusive combinations of features; rather, theinvention may comprise a combination of different individual featuresselected from different individual embodiments, as understood by personsof ordinary skill in the art.

Any incorporation by reference of documents above is limited such thatno subject matter is incorporated that is contrary to the explicitdisclosure herein. Any incorporation by reference of documents above isfurther limited such that no claims included in the documents areincorporated by reference herein. Any incorporation by reference ofdocuments above is yet further limited such that any definitionsprovided in the documents are not incorporated by reference hereinunless expressly included herein.

For purposes of interpreting the claims for the present invention, it isexpressly intended that the provisions of Section 112, sixth paragraphof 35 U.S.C. are not to be invoked unless the specific terms “means for”or “step for” are recited in a claim.

1-20. (canceled)
 21. A current difference sensor comprising: a firstconductor configured to conduct a first current that generates a firstmagnetic field component in a first direction; a second conductorconfigured to conduct a second current that generates a second magneticfield component in the first direction; a first magnetic field sensingelement, arranged at a first position, configured to sense the firstmagnetic field component and the second magnetic field component in thefirst direction; a second magnetic field sensing element, arranged at asecond position, configured to sense the first magnetic field componentand the second magnetic field component in the first direction; whereinthe first conductor and the second conductor, located proximate to oneanother, are configured to approximately cancel the first magnetic fieldcomponent in the first direction and the second magnetic field componentin the first direction in response to the first current flowing throughthe first conductor and the second current flowing through the secondconductor.
 22. The current difference sensor of claim 21, wherein thefirst conductor and the second conductor are configured to approximatelycancel the first magnetic field component in the first direction and thesecond magnetic field component in the first direction, at a firstlocation and at a second location, in response to the first currentflowing through the first conductor and the second current flowingthrough the second conductor.
 23. The current different sensor of claim21, wherein a sum of the first magnetic field and the second magneticfield at a first location is approximately equal to a sum of the firstmagnetic field and the second magnetic field at a second location. 24.The current difference sensor of claim 21, wherein the first current isapproximately equal to the second current.
 25. The current differencesensor of claim 21, further comprising circuitry, coupled to the firstmagnetic field sensing element and the second magnetic field sensingelement, configured to determine a difference between magnetic fieldsbeing sensed at a first location and a second location.
 26. The currentdifference sensor of claim 21, further comprising circuitry, coupled tothe first magnetic field sensing element and the second magnetic fieldsensing element, configured to determine a difference between the firstcurrent and the second current based on magnetic fields at a firstlocation and at a second location.
 27. The current difference sensor ofclaim 21, further comprising a plurality of magnetic field sensingelements, the first magnetic field sensing element and the secondmagnetic field sensing element being two of the plurality of magneticfield sensing elements, wherein the first magnetic field sensing elementand second magnetic field sensing element from the plurality of magneticfield sensing element comprise a lower sensitivity to a sum of the firstcurrent and the second current and a higher sensitivity to a differencebetween the first current and the second current with respect to othermagnetic field sensing elements of the plurality of magnetic fieldsensing elements.
 28. The current difference sensor of claim 21, furthercomprising a plurality of magnetic field sensing elements, the firstmagnetic field sensing element and the second magnetic field sensingelement being two of the plurality of magnetic field sensing elements,the plurality of magnetic field sensing elements arranged in a gridpattern with respect to one another across a first surface of a die. 29.The current difference sensor of claim 28, wherein the die is arrangedat a tilt angle with respect to a center of symmetry between the firstconductor and the second conductor.
 30. The current difference sensor ofclaim 28, wherein the die comprises a second surface that is opposite tothe first surface, and wherein the second surface is positioned closerto the first conductor and the second conductor than the first surface.31. The current difference sensor of claim 21, wherein the firstconductor and the second conductor are asymmetrical in shape withrespect to one another.
 32. A current sensor comprising: a plurality ofconductors comprising a first conductor configured to conduct a firstcurrent that generates a first magnetic field in a first direction, anda second conductor configured to conduct a second current that generatesa second magnetic field in the first direction, wherein the plurality ofconductors is configured to approximately cancel the first magneticfield in the first direction and the second magnetic field in the firstdirection at a first location and a second location; and a plurality ofmagnetic field sensing elements configured to sense the first magneticfield and the second magnetic field in the first direction at the firstlocation and the second location, and provide information regarding atleast one of a difference or a sum of the first current and the secondcurrent, based on the first magnetic field and the second magneticfield.
 33. The current sensor of claim 32, wherein the first current andthe second current are approximately equal.
 34. The current sensor ofclaim 32, wherein the first conductor is wider than the first conductor.35. The current sensor of claim 32, wherein the first conductor and thesecond conductor of the plurality of conductors form a U-shapedconductor element respectively with a connecting portion therebetween.36. The current sensor of claim 32, wherein the plurality of magneticfield sensing elements comprise: a first magnetic field sensing element,arranged approximately at the first location, configured to sense thefirst magnetic field and the second magnetic field in the firstdirection; a second magnetic field sensing element, arranged at thesecond location, configured to sense the first magnetic field and thesecond magnetic field in the first direction; a first orthogonalmagnetic field sensor element arranged opposite of the first magneticfield sensing element and forming a first half-bridge with the firstmagnetic field sensing element; and a second orthogonal magnetic fieldsensor element arranged opposite of the second magnetic field sensingelement and forming a second half-bridge with the second magnetic fieldsensing element.
 37. The current sensor of claim 36, wherein the firsthalf-bridge and the second half-bridge are configured to generatetemperature compensated signals, respectively.
 38. The current sensor ofclaim 32, wherein at least two conductors of the plurality of conductorsare laterally asymmetrical with respect to one another.
 39. A methodcomprising: inducing a first current to flow through a first conductorand a second current to flow through a second conductor; and eliminatinga magnetic field component in a first direction caused by the firstcurrent and the second current by positioning the first conductor andthe second conductor laterally asymmetrically relative to one anothersuch that the magnetic field component in the first direction isapproximately zero in at least two locations.
 40. The method of claim39, further comprising: determining a difference, or a sum, between thefirst current and the second current based on one or more magneticfields being sensed by a first magnetic field sensing element and asecond magnetic field sensing element at a first location and a secondlocation of the at least two locations.